This error occur when the virtual floppy auto install did not unmounted properly.
Simply do the following :
1. Shutdown the virtual machine
2. Disconnect the virtual floppy drive or set the drive to use the system floppy instead of image
3. Then, boot you’re guest and try again to install VMware Tools
If theses steps doesn’t work, you may need to delete and add again the virtual floppy device. Of course, you may delete forever the device if you don’t need it!